The present invention relates to a method for performing knee-joint replacement surgery. More particularly, the present invention relates to a method for performing a knee-joint replacement surgery with the aid of retractors retained by a support apparatus secured to a surgical table.
The knee-joint is the largest and the most complex joint in the body. The knee joint is the articulation of three bones consisting of the lower femur, the upper tibia and the upper tibia and the patella which is commonly known as the kneecap. Large ligaments attach the femur to the tibia to provide stability to the knee joint.
The joint surfaces of the femur, the tibia and the patella are covered with articular cartilage that cushions the bones. Along with the articular cartilage the femur and the tibia are separated by lateral and medial menisci which are pads of cartilage that act as shock absorbers between the two bones. All remaining surfaces of the tibia, femur and patella that make up the knee joint are covered by a synovial membrane that releases synovial fluid that lubricates the knee and reduces friction in a healthy knee to nearly zero.
When the knee-joint functions properly, the upper end of the tibia and the lower end of the femur glide with respect to each other and allow the knee to bend. The synovial fluid coated cartilage, including the menisci, separates the lower end of the femur and upper end of the tibia and provides cushioning between the tibia and femur similar to a shock absorber and smoothly articulate with nearly no friction.
The most common cause of chronic knee pain is arthritis of which osteoarthritis, rheumatoid arthritis and post traumatic arthritis are the most common forms. Osteoarthritis typically occurs after the age of 50 and is caused by the softening and wearing away of the cartilage including the menisci. As the cartilage is worn away, the tibia and femur rub against each other which causes pain and stiffness.
The second type of arthritis is rheumatoid arthritis which causes the synovial membrane to become thickened and inflamed, producing excessive amounts of synovial fluid which over-fills the joint space. The chronic inflammation can damage the cartilage and eventually cause cartilage loss, pain and stiffness.
The third type of arthritis is post traumatic arthritis which follows a serious knee injury. A knee fracture or severe tear of the knee ligaments may damage the cartilage over time. The damage to the cartilage causes pain and stiffness in the knee joint.
The arthritis in the knee can become painful to the point of extremely limiting the person's mobility. When medications such as analgesics cannot eliminate or make the pain manageable, an increasingly popular option is to have a total knee replacement operation where the damaged knee joint is replaced with an artificial knee-joint called a prosthesis.
The current procedure for performing a total knee replacement surgery is very taxing on the surgical personnel. An incision is made from the top of the knee exposing the patella. A retractor is disposed into the incision and to one side of the patella. The surgical personnel manually retract the patella to one side and use additional retractors to manually retract the flesh to expose the femur and tibia.
With the femur and tibia exposed, the joint is separated to gain access to either the end of the femur or the tibia typically by adjusting the position of the tibia which requires additional personnel. The ends of the femur and tibia are precisely cut and inserts are attached to each end of the bones. Typically, a metal piece made of highly polished stainless steel or titanium is inserted into the femur and an insert made of a durable, non-wearing plastic, typically polyethylene, is inserted into the tibia. The interface of the metal and the plastic provides a smooth moving joint that does not require lubrication.
One way to reduce the physical nature of the operation and the number of personnel required to perform the procedure is to use retractors secured to a support that is secured to a surgical table to retract the flesh to expose the surgical site. U.S. Pat. No. 6,315,718 discloses a table mounted retractor system for a method of hip retraction. The table mounted retractor system discloses using a table mounted support apparatus to support both flesh retracting retractors to expose the hip joint and bone retracting retractors to dislocate and displace the femural ball from the acetabulum.